1. Field of the Invention
This invention relates to filters and, more particularly, to a filter having a media component through which a fluid is passed and a frame for operatively mounting the filter.
2. Background Art
A multitude of components that treat fluids, such as air, exists in both residential and commercial environments. Different types of air treatment units abound and incorporate filters that are removable for cleaning and/or replacement. Within this category of products utilizing filters are air cleaners, heaters, coolers, etc.
Fresh or return air is caused to flow through filter media that intercepts and retains airborne particles. The filter media is commonly mounted in a frame that is designed to be conveniently placed operatively into a holder and removed therefrom for cleaning or replacement. These filters are generally designed to span the full areal extent of the intake region on the associated unit so as to not significantly block intake capacity while at the same time causing substantially all of the incoming air to be intercepted by the filter media.
Residential and industrial air treatment units often have a relatively large intake capacity, thereby necessitating that the filter media span continuously over a large area. The nature of the filter media and its form in the filters vary greatly. However, most commonly the filter media is lightweight and readily reconfigurable. As one example, sheets of material may be formed with accordion folds that effectively increase the filter contact area for incoming air. Other materials may be made with a honeycomb-type structure, or may be formed in a flat shape or otherwise.
The flexibility of the filter media generally makes it necessary that it be integrated into a frame that maintains shape and facilitates operative mounting of the filter within a complementary holder at an air intake location. Typically, the frame will surround the entire periphery of the filter media and extend around an area at least as great as the intake area for the associated unit. The frame thus determines the overall dimensions of the filter.
Virtually all commercial filters of the above type are made with a fixed configuration. While this fixed configuration affords a convenience in terms of handling the filter during installation and removal, it presents other problems common to “bulky” products.
One significant problem with these filters is attributable to their large size and their particular construction. Ideally, there is no obstructing component that blocks passage of air through the filter media aligned over an intake opening. As a consequence, the filter rigidity is attributable primarily to the peripheral frame. Since ideally the frame is made from lightweight and inexpensive or recyclable materials, the frame has a tendency to twist and bend when exposed to even relatively modest external forces. This property makes the filters prone to being damaged at times when the filters are being stored and transported. The weight of the filter itself may cause distortion if the filter is not adequately supported. This distortion may lead to a permanent set that changes the shape of the filter significantly enough that it may be difficult or impossible to conform the same to an accommodating holder.
As noted above, these fixed configuration filters may have a large overall volume. Bulk transportation may become difficult and/or expensive. If quantities of the filters are placed in master cartons, the cartons become large if any significant quantities of the filters are to be placed therein. The master cartons then become awkward to handle and difficult to store, not due to their weight, but rather to their overall size. As a result, shipping and handling costs may be sufficiently high that, when passed on to the consumer, the overall cost of each individual filter is appreciably and undesirably increased.
If the master cartons are made with adequate rigidity, the cartons themselves may become expensive. If the cartons are inadequately rigid, the filters are prone to being damaged as by being bent, twisted, or ruptured.
Handling of large cartons also has an adverse environmental impact. Aside from using a substantial amount of space in transportation vehicles, and thus accounting for significant fuel usage, the containers must be disposed of after use.
Another problem with a fixed configuration filter is that it will cooperate with only a single size holder. While the industry has standardized size for filters to a certain extent, there remains a demand for a number of differently sized “standard” filters. For those businesses selling the filters, demand for each different filter size must be estimated. At times, this is just an exercise of chance whereby there inevitably will result shortages of some sized filters and excesses of others.
At point of sale, and/or in staging areas, excess inventory for each filter size may be kept on hand to avoid shortages. Valuable space may be taken up by these filters on display racks and in warehouses.
A number of collapsible filter designs are disclosed in U.S. patents. The objective of these designs is to address some or all of the above-noted problems. However, for designs to be commercially feasible, they must be cost efficient to manufacture. At the same time, the collapsible designs must be user friendly. Consumers are currently accustomed to purchasing and handling filters in their final configuration so that assembly and removal each involves a simple translational movement relative to a holder. Complicated steps to convert a filter from a collapsed state into an operative state would make such a product commercially undesirable.
Further, it is important that the integrity of the filter, with a collapsing capability, be maintained, in each of its potentially multiple configurations.
To date, many of these objectives have been competing to the point that no commercially viable product has been devised. The industry continues to seek out affordable alternatives that address the limitations in the existing filter art.